We usually don’t think about the wonderful service fossil fuels provide in terms of being a store of heat energy for winter, the time when there is a greater need for heat energy. Figure 1 shows dramatically how, in the US, the residential usage of heating fuels spikes during the winter months.
Figure 1. US residential use of energy, based on EIA data. The category “Natural Gas, etc.” includes all fuels bought directly by households and burned. This is primarily natural gas, but also includes small amounts of propane and diesel burned as heating oil. Wood chips or other commercial wood purchased to be burned is also in this category.
Solar energy is most abundantly available in the May-June-July period, making it a poor candidate for fixing the problem of the need for winter heat.
Figure 2. California solar electricity production by month through June 30, 2022, based on EIA data. Amounts are for utility scale and small scale solar combined.
In some ways, the lack of availability of fuels for winter is a canary in the coal mine regarding future energy shortages. People have been concerned about oil shortages, but winter fuel shortages are, in many ways, just as bad. They can result in people “freezing in the dark.”
In this post, I will look at some of the issues involved.
 Batteries are suitable for fine-tuning the precise time during a 24-hour period solar electricity is used. They cannot be scaled up to store solar energy from summer to winter.
In today’s world, batteries can be used to delay the use of solar electricity for at most a few hours. In exceptional situations, perhaps the holding period can be increased to a few days.
California is known both for its high level of battery storage and its high level of renewables. These renewables include both solar and wind energy, plus smaller amounts of electricity generated in geothermal plants and electricity generated by burning biomass. The problem encountered is that the electricity generated by solar panels tends to start and end too early in the day, relative to when citizens want to use this electricity. After citizens return home after work, they would like to cook their dinners and use their air conditioning, leading to considerable demand after the sun sets.
Figure 3. Illustration by Inside Climate News showing the combination of resources utilized during July 9, 2022, which was a day of peak electricity consumption. Imports refer to electricity purchased from outside the State of California.
Figure 3 illustrates how batteries in combination with hydroelectric generation (hydro) are used to save electricity generation from early in the day for use in the evening hours. While battery use is suitable for fine tuning exactly when, during a 24-hour period, solar energy will be used, the quantity of batteries cannot be ramped up sufficiently to save electricity from summer to winter. The world would run out of battery-making materials, if nothing else.
 Ramping up hydro is not a solution to our problem of inadequate energy for heat in winter.
One problem is that, in long-industrialized economies, hydro capabilities were built out years ago.
Figure 4. Annual hydro generation based on data of BP’s 2022 Statistical Review of World Energy.
It is difficult to believe that much more buildout is available in these countries.
Another issue is that hydro tends to be quite variable from year to year, even over an area as large as the United States, as shown in Figure 4 above. When the variability is viewed over a smaller area, the year-to-year variability is even higher, as illustrated in Figure 5 below.
Figure 5. Monthly California hydroelectric generation through June 30, 2022, based on EIA data.
The pattern shown reflects peak generation in the spring, when the ice pack is melting. Low generation generally occurs during the winter, when the ice pack is frozen. Thus, hydro tends not be helpful for raising winter energy supplies. A similar pattern tends to happen in other temperate areas.
A third issue is that variability in hydro supply is already causing problems. Norway has recently reported that it may need to limit hydro exports in coming months because water reservoirs are low. Norway’s exports of electricity are used to help balance Europe’s wind and solar electricity. Thus, this issue may lead to yet another energy problem for Europe.
As another example, China reports a severe power crunch in its Sichuan Province, related to low rainfall and high temperatures. Fossil fuel generation is not available to fill the gap.
 Wind energy is not a greatly better than hydro and solar, in terms of variability and poor timing of supply.
For example, Europe experienced a power crunch in the third quarter of 2021 related to weak winds. Europe’s largest wind producers (Britain, Germany and France) produced only 14% of their rated capacity during this period, compared with an average of 20% to 26% in previous years. No one had planned for this kind of three-month shortfall.
In 2021, China experienced dry, windless weather, resulting in both its generation from wind and hydro being low. The country found it needed to use rolling blackouts to deal with the situation. This led to traffic lights failing and many families needing to eat candle-lit dinners.
Even viewed on a nationwide basis, US wind generation varies considerably from month to month.
Figure 6. Total US wind electricity generation through June 20, 2022, based on EIA data.
US total wind electricity generation tends to be highest in April or May. This can cause oversupply issues because hydro generation tends to be high about the same time. The demand for electricity tends to be low because of generally mild weather. The result is that even at today’s renewable levels, a wet, windy spring can lead to a situation in which the combination of hydro and wind electricity supply exceeds total local demand for electricity.
 As more wind and solar are added to the grid, the challenges and costs become increasingly great.
There are a huge number of technical problems associated with trying to add a large amount of wind and solar energy to the grid. Some of them are outlined in Figure 7.
Figure 7. Introductory slide from a presentation by power engineers shown in this YouTube Video.
One of the issues is torque distortion, especially related to wind energy.
Figure 8. Slide describing torque distortion issues from the same presentation to power engineers as Figure 7. YouTube Video.
There are also many other issues, including some outlined on this Drax website. Wind and solar provide no “inertia” to the system. This makes me wonder whether the grid could even function without a substantial amount of fossil fuel or nuclear generation providing sufficient inertia.
Furthermore, wind and solar tend to make voltage fluctuate, necessitating systems to absorb and discharge something called “reactive power.”
 The word “sustainable” has created unrealistic expectations with respect to intermittent wind and solar electricity.
A person in the wind turbine repair industry once told me, “Wind turbines run on a steady supply of replacement parts.” Individual parts may be made to last 20-years, or even longer, but there are so many parts that some are likely to need replacement long before that time. An article in Windpower Engineering says, “Turbine gearboxes are typically given a design life of 20 years, but few make it past the 10-year mark.”
There is also the problem of wind damage, especially in the case of a severe storm.
Figure 9. Hurricane-damaged solar panels in Puerto Rico. Source.
Furthermore, the operational lives for fossil fuel and nuclear generating plants are typically much longer than those for wind and solar. In the US, some nuclear plants have licenses to operate for 60 years. Efforts are underway to extend some licenses to 80 years.
With the short life spans for wind and solar, constant rebuilding of wind turbines and solar generation is necessary, using fossil fuels. Between the rebuilding issue and the need for fossil fuels to maintain the electric grid, the output of wind turbines and solar panels cannot be expected to last any longer than fossil fuel supply.
 Energy modeling has led to unrealistic expectations for wind and solar.
Energy models don’t take into account all of the many adjustments to the transmission system that are needed to support wind and solar, and the resulting added costs. Besides the direct cost of the extra transmission required, there is an ongoing need to inspect parts for signs of wear. Brush around the transmission lines also needs to be cut back. If adequate maintenance is not performed, transmission lines can cause fires. Burying transmission lines is sometimes an option, but doing so is expensive, both in energy use and cost.
Energy models also don’t take into account the way wind turbines and solar panels perform in “real life.” In particular, most researchers miss the point that electricity from solar panels cannot be expected to be very helpful for meeting our need for heat energy in winter. If we want to add more summer air conditioning, solar panels can “sort of” support this effort, especially if batteries are also added to help fine tune when, during the 24-hour day, the solar electricity will be utilized. Unfortunately, we don’t have any realistic way of saving the output of solar panels from summer to winter.
It seems to me that supporting air conditioning is a rather frivolous use for what seems to be a dwindling quantity of available energy supply. In my opinion, our first two priorities should be adequate food supply and preventing freezing in the dark in winter. Solar, especially, does nothing for these issues. Wind can be used to pump water for crops and animals. In fact, an ordinary windmill, built 100 years ago, can also be used to provide this type of service.
Because of the intermittency issue, especially the “summer to winter” intermittency issue, wind and solar are not truly replacements for electricity produced by fossil fuels or nuclear. The problem is that most of the current system needs to remain in place, in addition to the renewable energy system. When researchers make cost comparisons, they should be comparing the cost of the intermittent energy, including necessary batteries and grid enhancements with the cost of the fuel saved by operating these devices.
 Competitive pricing plans that enable the growth of wind and solar electricity are part of what is pushing a number of areas in the world toward a “freezing-in-the-dark” problem.
In the early days of electricity production, “utility pricing” was generally used. With this approach, vertical integration of electricity supply was encouraged. A utility would make long term contracts with a number of providers and would set prices for customers based on the expected long-term cost of electricity production and distribution. The utility would make certain that transmission lines were properly repaired and would add new generation as needed.
Energy prices of all kinds spiked in the late 1970s. Not long afterward, in an attempt to prevent high electricity prices from causing inflation, a shift in pricing arrangements started taking place. More competition was encouraged, with the new approach called competitive pricing. Vertically integrated groups were broken up. Wholesale electricity prices started varying by time of day, based on which providers were willing to sell their production at the lowest price, for that particular time period. This approach encouraged providers to neglect maintaining their power lines and stop adding more storage capacity. Any kind of overhead expense was discouraged.
In fact, under this arrangement, wind and solar were also given the privilege of “going first.” If too much energy in total was produced, negative rates could result for other providers. This approach was especially harmful for nuclear energy. Nuclear power plants found that their overall price structure was too low. They sometimes closed because of inadequate profitability. New investments in nuclear energy were discouraged, as was proper maintenance. This effect has been especially noticeable in Europe.
Figure 10. Nuclear, wind and solar electricity generated in Europe, based on data of BP’s 2022 Statistical Review of World Energy.
The result is that about a third of the gain from wind and solar energy has been offset by the decline in nuclear electricity generation. Of course, nuclear is another low-carbon form of electricity. It is a great deal more reliable than wind or solar. It can even help prevent freezing in the dark because it is likely to be available in winter, when more electricity for heating is likely to be needed.
Another issue is that competitive pricing discouraged the building of adequate storage facilities for natural gas. Also, it tended to discourage purchasing natural gas under long term contracts. The thinking went, “Rather than building storage, why not wait until the natural gas is needed, and then purchase it at the market rate?”
Unfortunately, producing natural gas requires long-term investments. Companies producing natural gas operate wells that produce approximately equal amounts year-round. The same pattern of high winter-consumption of natural gas tends to occur almost simultaneously in many Northern Hemisphere areas with cold winters. If the system is going to work, customers need to be purchasing natural gas, year-round, and stowing it away for winter.
Natural gas production has been falling in Europe, as has coal production (not shown), necessitating more imports of replacement fuel, often natural gas.
Figure 11. Natural gas production in Europe, based on data of BP’s 2022 Statistical Review of World Energy.
With competitive rating and LNG ships seeming to sell natural gas on an “as needed” basis, there has been a tendency in Europe to overlook the need for long term contracts and additional storage to go with rising natural gas imports. Now, Europe is starting to discover the folly of this approach. Solar is close to worthless for providing electricity in winter; wind cannot be relied upon. It doesn’t ramp up nearly quickly enough, in any reasonable timeframe. The danger is that countries will risk having their citizens freeze in the dark because of inadequate natural gas import availability.
 The world is a very long way from producing enough wind and solar to solve its energy problems, especially its need for heat in winter.
The energy supply that the world uses includes much more than electricity. It contains oil and fuels burned directly, such as natural gas. The percentage share of this total energy supply that wind and solar output provides depends on how it is counted. The International Energy Agency treats wind and solar as if they only replace fuel, rather than replacing dispatchable electricity.
Figure 12 Wind and solar generation for a category called “Wind, Solar, etc.” by the IEA. Amounts are for 2020 for Germany, the UK, Australia, Norway, the United States, and Japan. For other groups shown in this chart, the amounts are calculated using 2019 data.
On this basis, the share of total energy provided by the Wind and Solar category is very low, only 2.2% for the world as a whole. Germany comes out highest of the groups analyzed, but even it is replacing only 6.0% of its total energy consumed. It is difficult to imagine how the land and water around Germany could tolerate wind turbines and solar panels being ramped up sufficiently to cover such a shortfall. Other parts of the world are even farther from replacing current energy supplies with wind and solar.
Clearly, we cannot expect wind and solar to ever be ramped up to meet our energy needs, even in combination with hydro.
By Gail Tverberg
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